Easy pattern disc removal devices

ABSTRACT

In a cam controlled, needle jogging ornamental stitch sewing machine, a cam removal mechanism is provided for elevating a seated pattern cam from the interior portion of the sewing machine, to an accessible position. A trifurcated, resilient, bowed retaining means is slidable within an axial bore in a central hub and operatively connected to a spring biased plunger. When the pattern cam is in the seated position, the retaining means overlies the pattern cam. When the plunger is depressed, the retaining means is pushed below the seated cam until it underlies the cam, whereupon the spring biased plunger is released and the retaining means raises upwardly carrying the cam with it.

United States Patent Urciola Mar. 14, 1972 [54] EASY PATTERN DISCREMOVAL DEVICES [72] inventor: John A. Urciola, South Bound Brook, NJ.[73] Assignee: The Singer Company, New York, NY.

[22] Filed: Sept. 10, 1970 21] Appl. No.: 71,169

Primary Examiner-Andrew V. Kundrat Attorney-Marshall J. Breen, ChesterA. Williams, Jr. and Robert E. Smith [57] ABSTRACT In a cam controlled,needle jogging ornamental stitch sewing machine, a cam removal mechanismis provided for elevating a seated pattern cam from the interior portionof the sewing machine, to an accessible position. A trifurcated,resilient, bowed retaining means is slidable within an axial bore in acentral hub and operatively connected to a spring biased plunger. Whenthe pattern cam is in the seated'position, the retaining means overliesthe pattern cam. When the plunger is depressed, the retaining means ispushed below the seated cam until it underlies the cam, whereupon thespring biased plunger is released and the retaining means raisesupwardly carrying the cam with it.

3 Claims, 5 Drawing Figures Patented March 14, 1972 3,649,057

INVENTOR'. John A. UrcIoIa T ESS= ATTORNEY EASY PATTERN DISC REMOVALDEVICES BACKGROUND OF THE INVENTION In an ornamental stitch sewingmachine of the type described in US. Pat No. 2,862,468, Dec. 2, 1958, toR. E. Johnson for an Omamental Stitch Sewing Machine, the

stitch pattern is controlled by a stitch pattern cam which is housedwithin the sewing machine frame. The stitch pattern cam causes thelateral jogging of the needle bar and this forms a particular stitchpattern. It is desirable to be able to form a variety of differentstitch patterns, and for this reason, there are different cams availablewhich may be exchanged in the sewing machine frame with other stitchpattern cams so that the desired variety of stitch patterns may beformed.

The stitch pattern cam is usually mounted in the upper portion of theoverhanging arm of a sewing machine frame fast on a rotating cam shaft.The pattern cam, therefore, must be tightly mounted on the cam shaft inorder to rotate with the cam shaft without slipping. Access to theseated pattern cam is provided through a limited access opening in thetop surface of the overhanging arm of the sewing machine frame. Toexchange one pattern cam for another, the operator must reach throughthis limited access opening and pry the cam loose from its seatedposition. This procedure is often frustrating and may result in brokenfingernails and soiled fingers.

The stitch pattern cam is typically a flat disc with a central bossrising therefrom so that the operator will be able to exchange the camfrom the machine by grasping the boss portion of the pattern cam disc.This central boss adds to the height of the cam, making it approximatelythree times as high as the flat disc portion, thereby increasing thestorage area requirements threefold.

SUMMARY OF THE INVENTION In accordance with the present invention, asewing machine having a jogging or laterally oscillatory needlecontrolled by a pattern cam mounted on a rotating cam shaft, is providedwith a cam removal mechanism incorporated into the upper portion of thecam shaft. The cam removal mechanism, mounted on the cam shaft which mayhave a stack of permanently mounted cams thereon, includes a flangebeyond which the cam shaft extends. Above the flange, the cam shaft isdivided by radial slots into a plurality of vertical, spaced-apartsections comprising a central hub. Mounted within the cam shaft is aplunger which is spring biased into an up position. Cooperativelyassociated with the plunger, and axially slidable within the cam shaft,is a retaining means which has plurality of radially extending bowedfingers. Theses bowed fingers extend outwardly of the cam shaft in theslots between the plurality of spaced apart vertical sections in the camshaft. A pattern cam may be mounted onto the cam shaft and seated on acam seat supported by the flange when the bowed fingers of the retainingmeans overlie the cam. When the spring biased plunger is depressed, theretaining means is urged downwardly until its bowed fingers underlie thepattern cam, and then the plunger is released allowing the retainingmeans and the pattern cam to raise upwardly into an accessible position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of thecam removal mechanism of this invention as applied to a sewing machinecam shaft with the upper portion of the cam shaft cut away to show theinner portion of the cam removal mechanism, and also showing a patterncam in its seated position'on the cam shaft.

FIG. 2 is an elevational view similar to that of FIG. 1, with the lowerportion of the cam shaft partially omitted and showing the upper portionof the cam shaft with the plunger depressed and the retaining meansunderlying a pattern cam.

FIG. 3 is a view similar to that of FIG. 2, but showing the pattern camraised on the cam shaft.

FIG. 4 is a top plan view showing the cam removal mechanism without acam mounted thereon.

FIG. 5 is an exploded perspective view of the cam removal mechanism andthe pattern cam.

DETAILED DESCRIPTION OF THE INVENTION In an-omamental stitch sewingmachine, there may be provided means for laterally jogging the needlebar so that the needle will sew a zigzag pattern. The means provided isusually linkage which causes the needle bar to oscillate, a cam toprogram the lateral oscillations, and a cam follower to transmit the camprogram tothe linkage connected to the needle bar. The present inventionis useful in the above described embodiment in that it provides a simpleand effective means for removing the pattern cam from a sewing machineso that a different pattern cam may be inserted for sewing a differentpattern.

Only a sewing machine pattern cam shaft is illustrated in the drawings,it being understood that this cam shaft may be incorporated into anyconventional pattern cam controlled zigzag sewing machine. It shouldalso be noted that the cam shaft of this invention may also be formedwith permanent cams incorporated thereon as is known in the prior artbut not shown in the drawings.

An exchangeable pattern cam 11 may be mounted on a cam shaft 13-havingan axial bore 15. The cam shaft is rotatable about an axle 17, which maybe secured in a sewing machine frame (not shown). The top portion of theaxle is formed with a screw head 19 for adjusting the axle positionwithin the sewing machine. The cam shaft is caused to rotate by a drivengear 21 integral with the cam shaft and the cam shaft is retained on theaxle by a C shaped clip 23.

The upper portion of the cam shaft is split into three spaced apartvertical sections constituting a central'hub 27, with radial slots 29between each of the three vertical sections. A cam seat locator flange31 is formed between the spaced apart vertical sections and theremainder of the cam shaft; the flange, supporting a cam seat 33. Thecam seat is held to the flange by means of a pair of screws 35 whichpass through a pair of arcuate apertures 37 and are threaded into holes39 in the flange. The purpose of the arcuate apertures is to allow forangular adjustment of the cam seat. A vertical key 41 is integral withthe cam seat and extends parallel to the central hub providing a meansfor aligning the pattern cam to the cam shaft.

A coil compression spring 43 is mounted within the axial bore of the camshaft, having its lower extremity supported by and abutting the upperportion of the axle 17. Endwise slidable in a central bore 45 of abushing 47 threaded into central hub portion of thecam shaft is aplunger including a button portion 49, and a shaft portion 51terminating in a reduced shoulder portion 53. A cam retaining means 55is fixed to the shoulder portion of the plunger shaft by a C" shapedclip 57 which engages an annular groove 58 in the shoulder portion 53 ofthe plunger.

The retaining means includes a washer-like central portion 59 havingthree equally spaced radially outwardly and upwardly extending resilientfingers 61. The .upper extremity of each resilient finger contains acambered portion 63 which allows the resilient fingers to be smoothlyurged inwardly into the central hub as a cam is being inserted onto thecam shaft or as the plunger is being depressed to actuate the camremoval. The washer-like central portion of the retaining means engagesthe plunger shaft at its shoulder portion. The effect of thisconstruction is that the plunger and the retaining means both arepermitted to travel within the axial bore of the central hub in thevertical direction. Clearance recesses 65 are formed in the flange 31 toallow maximum travel of the retaining means.

As shown in the drawings each exchangeable pattern cam 11 is formed witha central opening 67 from which a radial cutout 69 extends. To seat thecam 11 on the cam seat, it is first necessary to align the centralopening 67 and the radial cutout 69 of the pattern cam respectively withthe central hub 27 and the vertical key 41 of the cam removal device.Once this is accomplished, a downward vertical force is exerted in thecam 11 which forces the plunger assembly including the retaining meansdownwardly. At some point in the downward movement of the pattern cam,the resilient arms of the retaining means will be urged radiallyinwardly into the central hub by the lower edge 71 of the pattern camcentral opening until the cam slips over the cambered portion of theresilient arms causing the plunger and the retaining means to pop up andlock the pattern cam onto the cam seat. Because the resilient arms ofthe retaining means are bowed radially outwardly they will then overliethe seated cam. The preceding sequence of operation is best followed byviewing the drawing in the order of FIGS. 3, 2 and 1.

To unseat a seated pattern cam, the plunger is depressed against theaction of the compression spring 43. As the plunger is depressed, theresilient arms of the retaining means bear against the upper edge 73 ofthe pattern cam central opening which causes the resilient arms totravel inwardly according to the curvature of the cambered portion untilthey slip below the seated pattern cam. At this point, the resilientarms again bow radially outwardly but now they underlie the pattern camand as the plunger assembly including the retaining means is releasedagainst the force of the compression spring 43 the plunger assemblyincluding the retaining means and the seated pattern cam are all carriedupwardly on the cam shaft where the cam will be accessible to theoperator. This operation is best followed in the sequence of FIGS. 1, 2and 3.

It will be understood that various changes in the details, material,arrangement of parts and operating conditions, which have been hereindescribed and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art without departingfrom the scope and principles of this invention.

The construction of this invention is thus of utmost simplicityrequiring one moving assembly comprising the plunger 51 with the patterncam retaining resilient fingers 61 attached thereto, and a coil spring43 urging the assembly upwardly. The resilient fingers 61 are sooutwardly bowed with the free ends inturned that the central opening 67of pattern cam may be forced past the fingers readily, or vice versa.The fingers may readily be forced through the central opening of apattern cam. The resilient fingers 61 thus either overlie a pattern camto retain it in place, or they underlie a pattern cam and serve as anintermediate element in biasing the pattern cam into a raised positionfor convenient exchange of pattern cams.

Having thus set forth the nature of the invention what we claim as new:

1. A device for releasing and elevating an exchangeable pattern cam discfrom a cam seat on a cam shaft in a sewing machine, including:

a. a hub portion on said cam shaft including a free extremity extendingfrom said cam seat;

b. said cam shaft being formed with an axial bore extending through saidhub portion with at least one radial slot opening from said bore to theexterior of said hub portion;

0. a plunger slidable in said axial bore;

d. spring means biasing said plunger toward the free extremity of saidhub portion;

e. a resilient pattern cam retaining finger carried by said plunger andlocated in said radial slot in said hub portion;

f. said resilient pattern cam retaining finger extending through saidhub portion to a position radially outwardly of said hub portion andincluding a free extremity bent inwardly and tenninating within saidslot 2. The device as set forth in claim 1 wherein three pattern camretaining fingers extend through three substantially equally spacedradial slots in the hub portion, the three retaining fingers beingattached to a washer-like central portion which is carried by theplunger.

3. The device as set forth in claim 1 wherein the axial bore of the camshaft hub portion accommodates a threaded bushing formed with an axialbore in which said plunger is slidably constrained.

1. A device for releasing and elevating an exchangeable pattern cam discfrom a cam seat on a cam shaft in a sewing machine, including: a. a hubportion on said cam shaft including a free extremity extending from saidcam seat; b. said cam shaft being formed with an axial bore extendingthrough said hub portion with at least one radial slot opening from saidbore to the exterior of said hub portion; c. a plunger slidable in saidaxial bore; d. spring means biasing said plunger toward the freeextremity of said hub portion; e. a resilient pattern cam retainingfinger carried by said plunger and located in said radial slot in saidhub portion; f. said resilient pattern cam retaining finger extendingthrough said hub portion to a position radially outwardly of said hubportion and including a free extremity bent inwardly and terminatingwithin said slot.
 2. The device as set forth in claim 1 wherein threepattern cam retaining fingers extend through three substantially equallyspaced radial slots in the hub portion, the three retaining fingersbeing attached to a washer-like central portion which is carried by theplunger.
 3. The device as set forth in claim 1 wherein the axial bore ofthe cam shaft hub portion accommodates a threaded bushing formed with anaxial bore in which said plunger is slidably constrained.